| 摘要: |
| 陆相湖盆致密油气是中国非常规油气资源最为现实的重要类型之一,储层研究是实现其高效勘探开发的核心与关键。基于前期研究成果,以松辽盆地南部白垩系泉头组、鄂尔多斯盆地三叠系延长组及准噶尔盆地吉木萨尔凹陷二叠系芦草沟组等典型致密油气藏为例, 厘定沉积成岩综合相的概念,形成沉积成岩综合相的测井识别技术,实现沉积成岩综合相的空间展布研究。 结果表明:致密油气储层储集物性极低,储集空间类型多样,发育微纳米级孔喉系统,孔喉连通性差;高压压汞、恒速压汞和核磁共振相结合,实现孔喉半径及分布的全面表征,原油优先充注于半径较大、连通性较好的原生孔隙中;将储层埋藏演化、成岩演化过程、物性演化过程与油气成藏过程相结合,建立成岩-油气成藏系统,划分“先成藏,后致密”和“先致密,后成藏”两种致密油气藏类型;“先成藏,后致密”型致密砂岩油气储层,成藏期储层物性好,现今为大孔细喉特征,孔隙度是储层评价的较优参数;“先致密,后成藏”型致密砂岩油气储层,成藏期储层物性差,现今为小孔细喉的特征,储层品质指数可以作为储层评价的关键参数。在此基础上结合储层有效性控制因素,采用灰色关联分析,形成致密油气定量评价分类方法。 |
| 关键词: 储层 成岩 物性 致密砂岩 陆相湖盆 |
| DOI：10.3969/j.issn.1673-5005.2019.05.002 |
| 分类号: |
| 文献标识码:A |
| 基金项目:国家自然科学基金项目(41702141,U1762217);国家自然科学基金委油气成藏机理创新研究群体(41821002) |
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| Several key issues related to tight oil and gas reservoir studies in lacustrine basin |
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CAO Yingchang1, XI Kelai1, LI Ke1, LIU Keyu1, ZHU Rukai2, YANG Tian1
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(1.Key Laboratory of Deep Oil and Gas in China University of Petroleum(East China), Qingdao 266580, China;2.Research Institute of Petroleum Exploration ＆ Development, PertroChina, Beijing 100083, China)
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| Abstract: |
| Tight oil and gas is becoming one of the most important and actual unconventional hydrocarbon resources in China. Generally, reservoir studies played the most significant role in making efficient tight oil exploration and development Several key issues were thoroughly discussed using as example the studies on tight oil and reservoirs from the Cretaceous Quantou Formation in Songliao Basin, Triassic Yanchang Formation in Ordos Basin and Permian Lucaogou Formation in Junggar Basin. Firstly, the concept of sedimentary-diagenetic facies was established, moreover, identification workflow and spatial distribution characteristics were determined as well. The reservoirs are characterized by quite low porosity and permeability, and variable pore space types. The pore-throat size of tight oil and gas reservoir is very small and poor in connectivity, but the radius is distributed at a large range of nano-to micro-scales. Combined with pressure-controlled mercury injection, rate-controlled mercury injection and nuclear magnetic resonance analysis, the pore-throat size distribution can be comprehensively measured. Crude oil is preferentially charged into primary pores with larger size and high connectivity. Integration studies on diagenesis, porosity evolution and oil emplacement under constraint of burial process were defined as “diagenesis-oil accumulation system”, which helped to divide oil accumulation processes into two types, namely oil emplacement before reservoir densification and oil emplacement after reservoir densification. For reservoirs with oil emplacement before reservoir densification, oil charging mainly happened in the period when reservoir had high qualities. At present, these reservoirs are characterized by large pores but small throat size. Thus, porosity can be regarded as a better parameter for reservoir evaluation. For reservoirs with oil emplacement after reservoir densification, however, oil charging mainly happened in quite low porosity and permeability conditions. At present, these reservoirs are characterized by small pores and narrow throats as well. So, pore-throat structures should be concerned in the reservoir evaluation studies, and reservoir quality index (RQI) was chosen as an optimal parameter for reservoir evaluation. Finally, a quantitative approach was proposed to evaluate reservoir quality based on the grey correlation analysis method. |
| Key words: reservoir diagenesis reservoir properties tight sandstones lacustrine basin |
